The Dutch authorities simultaneously raided about 100 buildings in Brabant and Limburg on Monday morning in an ongoing investigation into a network trading in synthetic drugs and cannabis. So far about 50 people were arrested, Omroep Brabant reports.

The raids are expected to continue for several hours. Some 1,500 employees of the police Defense, Public Prosecutor and the investigative department of the tax authorities FIOD are participating. There will definitely be more arrests during the course of the day, a spokesperson for the police said to Omroep Brabant.

The raids and arrests form part of an investigation that's been running for two to three years. It revolves around party rental store Party King on Ambachtsweg in Best, believed to be the cover for a kind of drug trafficking market place. A spokesperson for the police described the store as a "hotbed of crime" to the Volkskrant. According to him, dozens of suspects gather there.

The police watched Party King for some time and saw about 700 visitors come and go. According to the Volkskrant, they are all still being identified and the police are investigating which of them are guilty of criminal offenses. There are three prime suspects in the case. All three were arrested in the raids this morning.